The present invention relates generally to repair of integrated circuit memory and more particularly to using one set of fuses to control repair of multiple memories.
During the fabrication of an integrated circuit, defects may occur and render a circuit inoperable. Larger circuits and those with higher utilization of area are increasingly susceptible to defects. Memories embedded in integrated circuits are often large and dense. To achieve satisfactory manufacturing yield, memories may need to be designed to have reduced susceptibility to defects. Often this is accomplished by including spare or redundant sections into the memory. A defect in one section of the memory may be effectively eliminated by using the redundant section instead.
Some integrated circuits contain many individual memory modules. This commonly occurs when the integrated circuit is designed for communication system applications. Multiple memories may also occur in system-on-a-chip type integrated circuits. It may be impractical to share redundant memory sections between memory modules. Thus, each memory module will generally have its own redundant section.
Determination of when to use a redundant memory section is often controlled by fuses programmed during manufacturing of the integrated circuit. A fuse is generally physically large. Large size, however, is generally undesirable in an integrated circuit because of the associated reduction in performance and increase in cost. In an integrated circuit with many memory modules, the area required for fuses to control redundancy for each memory module may inhibit use of redundancy.